Scope:

ASTM C1895 is used to determine the Mohs scratch hardness of ceramic tile, glass tile, and other hard surfaces. Mohs scale is relevant for design, manufacturing, and quality control. Tile and glass manufacturers use this method for quality control and for selection of materials. Electronic manufacturers test the resilience of displays with this method.

Test Procedure:

The surface of the sample is scratched with an object of known hardness on the Mohs scale—Quartz (hardness of 9), the tip of a steel file (hardness about 7), the edge of a penny (3). If the object is harder than the sample, a definite scratch on the surface of the specimen can be seen. 

Sample size:

The sample should be a square of 6 × 6 inches (15 × 15 cm).

Result:

If the object of known hardness scratches the sample, then the object is harder than the specimen. But if the object cannot scratch the sample, then the sample is harder than the object and so on. If both the objects are equal in hardness, barely any scratches can be seen. Based on the observations, the sample gets a position on Mohs scale.